Since rate of absorption of UK-116,044 might be reduced during a migraine attack as a result of reduced gastric motility, the primary objective of this study is to measure plasma concentrations of UK-116,044 after a single oral dose in two situations in the same individuals, i.e., during a migraine attack and during an attack-free period. A secondary objective will be to determine apparent efficacy of UK-116,044 during an attack in relation to changing plasma drug concentrations.